Today in buildings or any other constructions, the above mentioned fire detecting system is employed.
Conventionally, in order to test fire detectors in such a system, people go over to each respective place where the fire detector is installed, and confirm the operability of each fire detector by raising its temperature using, for instance, a cigarette lighter, or by generating smoke artificially. The test method in which an electrical change to actuate a fire detector is applied to a fire detector to be tested is also known. Even by this method, the inspector must go over to the place where the detector in question is installed. The electrical change can be supplied from the receiving unit side. But a plurality of fire detectors are connected to one alarming line, and therefore, the inspector cannot identify which detector has been actuated, and he cannot select and test a particular detector, either.
I am proposing a selectively actuatable fire detector for the above-mentioned fire detecting system, which counts number of pulses sent from the receiving unit by way of an alarming line, actuates itself when it is designated by the number of pulses, and can reset itself by a second voltage which exceeds a predetermined value, in the simultaneously filed U.S. patent application Ser. No. 351,916, the content of which is incorporated in this application by reference. The invention of this application is directed to a test circuit which is used for testing a plurality of fire detectors in the above-mentioned fire detecting system.
A plurality of fire detectors are connected to one alarming line extending from a section relay installed in the receiving unit of the fire detecting system. Although it is possible to test by disconnecting the alarming line from the section relay, connecting it to a special test apparatus, and giving a predetermined number of pulses for each detector, it is quite troublesome. Also, if a fire breaks out when fire detectors are being tested in this manner, the system cannot give a fire alarm.
The purpose of this invention is to provide an operation test circuit for fire detectors which can be used in the state that all fire detectors are connected to a receiving unit.